A comparison of metals in sediments and water in the River Nahr-Ibrahim,Lebanon: 1996 and 1999

Rivers whose basins are underlain by carbonate rocks exhibit high pH, lower desorption of metals and possess high buffering capacity against acidic inputs to the river. The catchment of River Nahr-Ibrahim, Lebanon, is largely underlain by limestone. Compared to neighbouring countries, Lebanon is relatively fortunate since precipitation is high. However, recently a warming in temperature and a drop in precipitation has occurred, thus causing low water levels in rivers. The objective of this study is to investigate the variation of the total metal content (Fe, Mn, Zn, Cu, Pb and Cd) in bed sediments and water of River Nahr-Ibrahim between 1996 and 1999 (two years); and relate these variations to the effect of changes in human activities and/or due to the variations of precipitation rate, temperature and pH of water. Bed load sediments and stream water were collected simultaneously from five sampling sites. Water pH and temperature were determined in situ. Sediment samples were dried at room temperature and sieved; the sediment size <75 m size was retained. Water was analysed for major constituents and trace metals. Metals were extracted from sediments with aqua regia. Metal concentration in water and sediments were determined using ICP-MS technique. Data revealed a drop in metal concentrations (Zn, Cu, Pb, Cd) in sediments at quarry site after its closure. The decrease in precipitation rate, lowering the level of water and the dilution of industrial discharges and decrease in water pH led most probably to the desorption of metals from sediments into the water.     

Evaluating the seasonal changes of water quality of the Değirmendere and Galyan Rivers (Trabzon, Turkey)

The De?irmendere and Galyan (De?irmendere tributary) Rivers that discharge their water into the Black Sea are important watersheds in the northeastern part of Turkey. Water quality parameters were sampled from 1997 through 2001 for each year at five sites (three for Galyan, two for Degirmendere) along 29 and 42 km gradients, respectively covering all seasons. Surface water was collected from the sites and analyzed for temperature, total alkaline (MAAL), total dissolved solids (TDS), dissolved oxygen (DO), pH, conductivity (EC), nitrate (NO3), nitrite (NO2), total hardness (TH), phenolphthalein alkalinities (PAL) and organic matter (PV). Seasonal changes of water quality were analyzed statistically for both Rivers and evaluated according to the TS 266, EU and WHO standards. The analysis of variance results showed that Ca, Mg, MAL, NO3, pH, TDS and TH parameters of the De?irmendere River and Ca, DO, EC, MAL, NO3, pH and TH parameters of the Galyan River showed seasonal differences (p<0.05). The maximum values of the water pollution parameters for the two Rivers were below the threshold values throughout the study period. When both Rivers were compared, the mean values of the pollution parameters of the Degirmendere River were higher than those of the Galyan River and very close the limits. The results indicate that both Rivers can be used for the production of potable water during all seasons but only with an advanced treatment in the De?irmendere and a moderate treatment in the Galyan River, and for indirect and non-contact recreational activities.     

The performance of biological and tertiary wastewater treatment procedures for rotaviruses A removal

Environmental Science and Pollution Research - Enteric viruses, generally found in sewage, are recognized as the main cause of waterborne and foodborne public health outbreaks. Among leading...     

Environmental impact of seawater desalination plants

Enormous amounts of seawater are desalted everyday worldwide. The total world production of fresh water from the sea is about 2621 mgd (9.92 million m³ day^-1 1985 figures). Desalting processes are normally associated with the rejection of high concentration waste brine from the plant itself or from the pretreatment units as well as during the cleaning period. In thermal processes, mainly multistage flash (MSF) thermal pollution occurs. These pollutants increase the seawater temperature, salinity, water current and turbidity. They also harm the marine environment, causing fish to migrate while enhancing the presence of algae, nematods and tiny molluscus. Sometimes micro-elements and toxic materials appear in the discharged brine.This paper will discuss the impact of the effluents from the desalination plants on the seawater environment with particular reference to the Saudi desalination plants, since they account for about 50% of the world desalination capacity.     

Bias correction of regional climate model simulations for the impact assessment of the climate change in Egypt

This study projected the future temperature change for Egypt during the late of this century (2071–2100) for three representative concentration pathways (RCP2.6, RCP4.5, and RCP8.5), by correcting regional climate model (RCM) simulations of average, maximum, and minimum daily temperature with reference to observed data of 26 stations. Four commonly used methods of bias correction have been applied and evaluated: linear scaling, variance scaling, and theoretical and empirical quantile mapping. The compromise programing results of the applied evaluation criteria show that the best method is the variance scaling, and thus it was applied to transfer the correction factor to the projections. All temperature indices are expected to increase significantly under all scenarios and reach the highest record by the end of the century, i.e., the expected increase in average, maximum, and minimum temperature ranges between 4.08–7.41 °C, 4.55–7.89 °C, and 3.88–7.23 °C, respectively. The largest temperature rise will occur in the summer, with the highest increase in the maximum (minimum) temperature of 10.9 °C (10 °C) in July and August under RCP8.5. The maximum (minimum) winter temperature, on the other hand, will drop by a maximum of 2 °C (1.35 °C) under RCP2.6. The Western Desert and Upper Egypt are the regions most affected by climate change, while the northern region of Egypt is the least affected. These findings would help in impact assessment and adaptation strategies and encourage further investigation to evaluate various climate models in order to obtain a comprehensive assessment of the climate change impacts on different hydrometeorological processes in Egypt.

     

Development of a Natural Chewing Gum from Plant Based Polymer

In this study, Kenger gum obtained from Kenger plant (Gundelia tournefortii) was used in the production of biodegradable and edible chewing gum. Kenger gum was able to be softened by thermal process to improve its textural properties. 80% methanolic extract of gum showed 195.6 gallic acid equivalents (GAE) mg/100 g gum antioxidant activity and 17.9 mm inhibition zone for Escherichia coli O157:H7 as an antimicrobial activity. Softened Kenger gum was also characterized by texture properties, scanning electron microscope (SEM) images and chemical compositions. Hardness value of gum decreased from 864 to 238 g which was comparable to commercial chewing gums. Softened Kenger gum was observed to be a perfect substitute for a synthetic gum base in the production of a conventional chewing gum. Moreover, resilience value was remarkably found to be the best standard parameter to select chewing gums with desired textural properties.     

Characterization of municipal solid waste temporary storage sites: Risks posed to surrounding areas as a consequence of fire incidents

In this study temporary storage sites of municipal solid waste were characterized based on their potential social, health and environmental impacts as a consequence of spontaneous fires, by employing Boolean as well as weighted-linear-combination approaches in connection with various fuzzy set functions of population density around the storage sites. Sweden was used as the case study and data from 105 storage sites were analysed; of these, 38 were identified to be posing high risk for downwind residing population. Furthermore, during the past 10 years, the fire frequency and the average population residing within a radius of 1, 2, and 3 km were found to be comparatively higher for storage sites owned by private companies than for those owned by municipalities. The study provided first-cut information of poorly sited temporary storage sites and can help in formalizing the comprehensive risk analysis in the future.